A preferred embodiment of the present invention generally relates to improvements in electrical connectors that connect printed circuit boards to one another and more particularly relates to electrical connectors that orthogonally connect, or mate, printed circuit boards.
Various electronic systems, such as computers, comprise a wide array of components mounted on printed circuit boards, such as daughterboards and motherboards that are interconnected to transfer signals and power throughout the systems. The transfer of signals and power between the circuit boards requires electrical connectors between the circuit boards that are typically through a backplane. The backplane supports part of an electrical connector that joins the two circuit boards.
Typically, a backplane is a printed circuit board that mounts into a server and communication switches. Multiple daughter cards are plugged into the backplane. One circuit board connects to another circuit board via connectors held in the backplane. Hence, in the past, in order for one circuit board to connect to another circuit board, a backplane was required as a conduit there between. As more circuit boards are required, more connections are required with the backplane. Generally, the circuit boards are aligned in parallel, such as a common plane or in parallel planes. The common parallel or planar alignment of multiple circuit boards is, in part, due to the need to afford a space-efficient and good signal quality connection with the backplane.
However, connecting circuit boards via a backplane leads to the potential for signal interference. Because the circuit boards are all connected via the backplane, signals from the various circuit boards may interfere with each other, especially as the signals travel through the common backplane. Additionally, signal strength may be attenuated as signals travel through the backplane. In general, signals passing between two daughterboards pass through at least one connector when input to the backplane and one connector when output from the backplane. The signal is attenuated at each connector.
Thus a need has existed for an electrical connector that directly connects circuit boards. Specifically, a need has existed for an electrical connector that connects circuit boards without a backplane, thereby improving system performance while reducing signal interference and signal attenuation.
At least one embodiment of the present invention relates to an electrical connector assembly that includes two groups of circuit boards, or wafers, that mate with, or connect to, one another in an orthogonal, or non-parallel manner. The electrical connector includes a plurality of circuit boards; a first connector housing including channels adapted to retain the first group of the circuit boards; a second connector housing also including channels adapted to retain the second group of the circuit boards; and a board interface located between the first and second connector housing. The first connector housing may be a receptacle connector, while the second connector housing may be a plug connector, or vice versa.
The channels in the first and second connector housings, are aligned parallel to, and retain, the first and second groups of circuit boards parallel to the first and second circuit board planes, respectively. In at least one embodiment of the present invention, the first circuit board plane intersects the second circuit board plane along a line extending along a length of the first and second connector housings. The first connector housing, such as a plug connector housing, and the second connector housing, such as a receptacle connector housing, have mating faces that mate with each other in a non-planar interconnection. The non-planar interconnection joins the plug mating edges at an angle to the receptacle mating edges.
The board interface is formed as part of one of the first and second connector housings. The board interface includes opposing mating faces of the first and second groups of circuit boards that join the first group of circuit boards in a non-parallel relationship to the second group of circuit boards. Preferably, the circuit boards are joined orthogonally. The opposing faces include first and second sets of slots that receive the first and second groups of circuit boards, respectively. The first set of slots are aligned transverse to the second set of slots. Additionally, the opposing faces of the board interface may include first and second sets of passages orthogonally joining said first group of circuit boards to the second group of circuit boards.
Each circuit board includes signal and ground contacts along an edge joining the board interface. The signal contacts on one circuit board in the first group of circuit boards electrically engage the signal contacts on at least two circuit boards in the second group of circuit boards, and vice versa.
The electrical connector also includes card-edge terminals that electrically interconnect the first and second groups of circuit boards. The card-edge terminals include a first contact surface on one end arranged to engage a first circuit board and a second contact surface on an opposite end arranged to engage a second circuit board. The first and second contact surfaces orthogonally face one another.
Each circuit board includes signal and ground contacts along an edge joining the board interface. The signal contacts on one circuit board in the first group of circuit boards electrically engage signal contacts on at least two circuit boards in the second group of circuit boards, and vice versa.
One embodiment of the present invention includes a plug connector that includes plug slots defining a plug plane and, a receptacle connector that includes receptacle slots defining a receptacle plane. The plug slots and said receptacle slots receive plug circuit boards and receptacle circuit boards, respectively, along the plug plane aligned in a non-parallel, transverse, or otherwise non-parallel relation to the header plane.